<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title></title>
    <script src="js/jquery.js"></script>
    <script src="js/chatab.js"></script>
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</head>
<body>

    <header>
        <nav>
            <ul>
                <li class="tabin">标签1</li>
                <li>标签2</li>
                <li>标签3</li>
            </ul>
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    <div class="contentfirst content">
        内容1
    </div>
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        内容2
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        内容3
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</body>
</html>
